My 9 yo has alt accounts I didn't setup, that's how easy Roblox is. I have MC/Microsoft account info for like 10 people, mostly family/friends kids, in my password manager because their parents were fine with them playing, but didn't want to deal with account management. Every sleep over starts with me logging everyone in on the various available devices, with their parents on standby to help with the multi-factor shitstorm that ensues.

Roblox is getting pretty bad though with age verification, and they will NOT help recover a lost/hacked account no matter how much money was spent on it. 5 year account, likely thousands of dollars in robux spent on it, kid clicked a bad link and it's gone. Roblox just responds they can't help, even though the original email address was verified, and used 2 factor auth through its history. They used to be helpful, they don't care anymore.